Flawed reasoning and Fallacies.
'Fallacy' is often said vaguely to mean any falsehood.
Used more specifically 'fallacy' can either be:
- The flaw itself
- A claim or belief based on flawed reasoning
There are a lot of ways to describe them, and names for them. The more common names are sometimes referred to as the "Classic Fallacies". For AS/A2 Critical you need to be able to recognize, describe and name a number of common (classic) fallacies.
The definitions/descriptions of fallacies: (with examples)
Ad hominem: This is where the argument challenges the author of an argument / the holder of a belief rather than the claim or reasoning behind the argument.
Eg:  The dinner lady is in support for the new healthy eating scheme for dinners, the dinner lady eat's 20 chocolate bars a day and no fruit or vegetables, this discredits any possible positive impact the scheme would have.
The dinner lady's eating habits don't discredit the scheme, though they might discredit her.
NOTE: challenging the author isn't always fallacious. For example if the argument is about the credibility/unbiased nature of a claim then it might be fully justified to challenge the authors motives/honesty etc.
In Latin 'Ad hominem' means literally 'at the man / person'
Tu quoque / justifying one wrong by another:
You should be familiar with the expression two wrongs don't make a right. The expression holds true for arguments in critical thinking.
Example:  You can't tell me to not go out and stay at home and revise, yesterday you were out all day, came back and went out to a party!
The second line of  isn't grounds for the conclusion (line 1), though it might be grounds for saying the person  is aimed at needs to do more revision
'Tu quoque' literally means 'you too'. However it is still a fallacy when said in third person.
Eg:  "Kate was justified in saying she shouldn't do anymore work when she's done more than the rest of the class".
One of the fallacies in  is still tu quoque, even though it's said in third person.
Straw man is misrepresenting / distorting / an opposing viewpoint/argument in such a way that it can easily be described as a weak argument.
eg:  Sophie wants a new teacher, this is proof that all teachers in her school are incompotent.
The speaker in  is wrong as there might be many reasons why Sophie wants a new teacher, some examples are: her current teacher is retiring soon, her current teacher is related to her so she is embarrassed.
A slippery assumes a small change or privilege will lead to extremes.
eg:  Allowing students…